One of England’s finest historic wreck dives has been upgraded with new underwater trail stations, photography and a virtual tour, allowing both divers and non-divers to explore the remains of the eighteenth-century warship.
HMS Colossus Wreck Trail
One of Britain’s most celebrated historic wreck dives has been given a new lease of life ahead of the 2026 diving season. Historic England, working with volunteer divers from the Cornwall and Isles of Scilly Maritime Archaeology Society (CISMAS), has refurbished the underwater dive trail on the Protected Wreck Site of HMS Colossus, making the site easier to explore both underwater and online.
The improvements include new underwater trail stations, updated waterproof guides, fresh photography and video, and a new virtual tour that recreates the dive experience for people unable to visit the wreck in person.
A warship with a remarkable history
HMS Colossus was a 74-gun third-rate ship of the line launched at Gravesend in Kent in 1787. During just over a decade of service, she participated in several major naval campaigns of the French Revolutionary Wars, including actions at Toulon, Groix, Cape St Vincent and Cádiz.
In December 1798, while seeking shelter from severe weather off the Isles of Scilly, the ship’s anchor cable parted and she was driven onto rocks near Samson Island. Although 594 of the 595 people aboard survived, the vessel broke apart during the following days, scattering its remains across the seabed.
The wreck later became famous for another reason. Among its cargo was part of Sir William Hamilton’s renowned collection of ancient Greek pottery. More than 30,000 pottery fragments recovered from the site are now held by the British Museum.
Exploring the wreck
The refurbished dive trail now consists of two circular underwater routes linking the principal archaeological features, marked with numbered seabed markers and an improved waterproof guide.
Divers can follow the line of cannon that crashed through the gunports as the ship rolled onto its side, examine muskets scattered across the seabed and explore surviving hull timbers and rudder fittings. Some of the guns measure 2.75 metres in length and weigh almost two tonnes.
In addition to its historical value, the wreck has become a thriving artificial reef that supports abundant marine life, making it an attractive site for both maritime archaeologists and recreational divers.
Heritage beneath the waves
HMS Colossus is one of only 57 Protected Wreck Sites in England, designated under the Protection of Wrecks Act 1973 because of its extraordinary historical and archaeological importance.
Access is restricted to licensed divers to help protect the site for future generations, but Historic England has also launched an interactive virtual tour featuring 3D models, underwater photography and video footage that closely follows the physical dive trail.
The project also provided an opportunity to assess the condition of the wreck. Volunteer divers removed marine growth from key archaeological features, improving both visibility and long-term monitoring of the site’s preservation.
Bringing maritime heritage to new audiences
For many divers, HMS Colossus has long been regarded as one of Britain’s premier archaeological wreck dives. The latest improvements make the site easier to access than ever, whether explored underwater or from home.
The project additionally emphasises the important role volunteer divers continue to play in documenting, monitoring and conserving underwater cultural heritage. By combining archaeological expertise with modern imaging techniques and virtual interpretation, Historic England hopes to inspire a wider appreciation of one of Britain’s most significant naval wrecks.
